Fluid-pressure brake



Feb. 17,A 1925- 1,525,777

v w. E. DEAN FLUID PRESSURE BRAKE Original Filed June 28, 1925 9 INVENTOR WILLIAM E. DEAN BYWMW ATTORNEY Patented Feb. 17, 1925.

UNITED STATES PATENT OFFICE.

WILLIAM E. DEAN, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE WESTING HOUSE AIR BRAKE COMPANY, OFWILMERDING, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

FLUID-PRESSURE BRAKE.

Application led June 28, 1923, Serial No. 648,274. Renewed July 24, 1924.

new and useful Improvements in Fluid-Pres-` sure Brakes, of which the following is a specification'. i

Thisinventionrelates to fluid pressure brakes, and more particularly to a triple valve device having means for eti'ecting a graduatedrelease of the brakes.

The principal object of `myinvention is to providemeans for cutting out the graduated release feature of a certain type of graduated releasetriple valve device.

In the accompanying drawing; Fig. 1 is a sectional view of a triple valve device with my improvement applied thereto; and Fig. 2 a diagram showing how the triple valve device is associated with the brake rigging `of the car.

As shown in the drawing, the triple valve device may comprise a casing 1 having a piston chamber 2 connected to the usual brake pipe 3 and containing piston 4 and having a. valve chamber 5 connected to a reservoir@ and containing a main slide valve 7 and a graduating slide valve 8, adapted to be operated by said piston.

Associated with the casing 1 is a brake cylinder9 containing a brake cylinder piston 10 having a piston rod 11, the piston chamber 12 having a passage 13 leading to the seat of slide valve 7 and also associated with casing 1 is a cylinder 14 containing a` The piston 15 having a piston stem 16. chamber 17 at one side of piston 15 has a passage 18 leading to the seat of slide valve 7 and chamber 19 at the opposite side ot" provided withtwo operating positions and in one position, a cavity 24 connects a passage 25 leading to chamber 17 with a passage26lead1ng to piston chamber 19, so

that direct releasev` may bey provided `in this position and in the other position, communication between the chamber 17 and chamber 19 is cut otl1 so as to permit the triple valve device to operate as a graduated release triple. As shown in Fig. 2, the piston rods 11 and 16 are connected to the brake rigging A of thecar, so that when the piston 1.0 is `moved outwardly'the brakes will be applied.

In operation, fluid supplied to the brake Y i pipe 3 Hows to piston chamber 2 and shifts piston 4 to release position, as shown in Fig. 1. In this position, the brake cylinder piston chamber 12 is connected to the exhaust through passage 13, restricted port 27 in main slide valve 7, cavity 2S in slide valve 8, port 29 in slide valve 7 and exhaust port 30. The chamber 17 is charged with fluid from the brake pipe 3 through passage 31, port 32 in slide valve 7, cavity 33 in slide valve 8, port 34 in slide valve 7 and passage 18. The piston 15 is moved upwardly by the pressure otfluid supplied to chamber 17 to the position shown in Fig. 1, the movement being assisted by the Yfact that the area o-t piston rod 16 is subject to atmospheric pressure. In this position, communication is established from chamber 17 to passage 36. Fluid then flows through passage 36 to valve chamber 5, and thence through passage 37 to piston chamber 19 and the reservoir (i.

llVith the cock 21 in graduated release position, as shown in Fig. 1, when the brake pipe pressure is reduced Vto eiiect a service application of the brakes, the higher pressure in valve chamber 5 shifts piston 4 to its extreme left hand position. The initial movement ot the piston 4 operates slide valve 8 without moving slide valve 7 so as to close the exhaust communication from the brake cylinder and also cut oit communica tion from the brake pipe to the chamber 17. Upon movement of the main slide valve 7 to service application position, fluid is supplied from chamber 17 `to the brake cylinder, through passage 18, port 38 in slide valve 7, cavity 39 in graduating slide valve 8, port 40 in slide valve 7, and passage 13.

The brake cylinder piston 10 is then moved sure in` chamber 17 is reduced by flow to the brake cylinder, the piston 15 is moved downwardly by the higher pressure in chainbei' 19. The downward movement .of piston 15 enlarges the volume of chamber 19 and this chamber being open to valve chamber and reservoir 6, the pressure in the combined volume is reduced in proportion to the increase in volume. Villien the pressure in valve cliaiiibei 5 has been reduced to a point slightly less than the reduced brake pipe pressure acting in piston chamber 2, the piston et will be shifted to the right to service lap position, in :which the graduating slide valve 8 has been moved so as to cut olf communication through which fluid is supplied. from the chamber 17 to the brake cylinder chamber 12,

If it is desired to effect a graduated re lease of the brakes, the brake pipe pressure is increased-to a pointsliglitl'yiA exceeding.;` Pistonv .Y 4 is thenrnioved by thehigher brakepipe the pressure 'in valvev chamber Y5.

pressure to release position, .in .which fiuid is released from b vake cylinderf chamber 12 to the exhaust port Othroughthe .restricted port 27. At the saine time, duid is sup-y plied from the brake pipe to chamber 17 through passa'geBL port 32, vcavity .33, port 84, and vpassage 1S and when the pressure in chamber 17 has been increased -to apoint exceeding thepressure in chamber 19, taking linto account the fact that the differential area of piston rod 16 is exposed to atmospheric pressure, the piston will -be moved` upwardly. The upward movement of piston 15 will reduce the -volume of chamber 19 and will thus increase th'epressure-in valve chamber 5 and reservoir V6 and when the pressure in valve chamber 5 has been increased to a point slightlyexceeding.- the pressure, in the brake pipe and in pistonV chamber 2, the piston t will be movedV from release-position to -release lap position,` in

which communicationfrom the brake cyliiider to the exhaust is cut off and in which communication from the brake pipe to chainber 17 is closed.

It will be evident that the vbrake cylinder pressure may be further reduced by making a further slight'increase in brake pipe `pressure, when the above described operation will be repeated.-

In order to ensure thedesired operationl in effecting graduated.releasefas above"de. scribed, it is necessary -to restrict the`dis-Y charge-offluid from the brake cylinder, as at the restricted port 27, in order* to 4provide a sufficient time interval for tliepres'-k sure in chainber'17 to be increased by. 'flowA from the brahe'pipe bef'oiexthefbrakeicylin# der pressure is reduced too inuch,'since itV is necessary that piston 15 be moved upwardly by the increase in .pressure in. chainbei' 17 V4in order thatthe pressure in valve chamber 5 may'beincreasedtfo effect the movement of the triple valve parts to the graduated release lap position.

In some instances, graduated release may not be necessary, as where a train is operating on long level stretches of road and in such -cases y'it may be rdesirablel to 'sup press the graduated release-feature in order to prevent delays caused -by undesired graduated release actioii. Such undesired graduated "releasemay be produced even when a direct release is intended, due to the sensitive character of thel triple valve device, and

to graduated release-lap position, when the brakelpipe, ,pressure is increased to effect the release of the brakes.

According to inyfinventon, by turning the cock 321110 .its direct, release positioii the chamber, 17 is connectedzto chamber 19 through passage 25, cavity 24, and vpassage 26, so that the'valve chamber 5, the reservoir ,its inherent tendency to move from release 6, andichambe'il' being ,directly connected Y together, the total volume `acts as an auxiliary reservoir and is not influenced by the piston 15 and it will'befevidentthat the triple valve device will'now operate as an ordinary triple valve device to supply fiuid from the auxiliary reservoir, volume to the `brake cylinder upon a reductionV in brake pipe pressure and to open' communication tor releasing ,fluidL from the brake cylinder, when the bralreipipe pressure is increased. i

Having-now described my invention, what- I claim as new and Ydesire to secure by VI ietters Patent, is

1. In a fiuid pressure brake, the combination wit-ha brake pipe, brakefcylinder, a reservoir, a chamber, a valve device subject to the opposing pressures of the brake pipe and said reservoir and operated upon a reduction in brake pipe pressure for supplying fluid from said chamber :to the brake cylinder, and a lpiston movable according to the opposingpressures of said reservoir and said chamber, of a, valve having a position in which communication' is established between said chamber Iand said reservoir.

2. In a fluid vpressure brake, the combination with 'a brake pipe, brake cylinder, a reservoir, a chamber, a valve device subject to the opposing pressures of the brake pipe' and said reservoir ando'perated upon a reductioniii brake pipe press'ui'etoi"'supplying Huid from said chamber to' the Lbrak'e cylinder, and a' piston'n'iovable according to the lll) opposing pressures of the reservoir and the brake pipe, valve. means operated by said piston upon e reduction in brake pipe pressure ior supplying fluid from said cham- 5 ber to the brake cylinder and upon an increase in brake pipe pressure for releasing luid from the brake cylinder, and a movable abutment separating said chamber from said reservoir, of a manually operable Valve having a position for establishing oommuni- 10 cation from said chamber to said reservoir.

In testimony whereof I have hereunto set my hand.

WILLIAM E. DEAN. 

